1. Field of the Invention
This invention relates to a novel triazine addition compound, a flame-retarded polyamide composition containing the triazine addition compound, and a process for the preparation of the triazine addition compound. The novel triazine addition compound imparts an effective flame-retarding property to a polyamide without deteriorating appearance and properties of a molded product produced therefrom.
2. Description of Prior Arts
It has been heretofore known that melamine, cyanuric acid or isocyanuric acid can be incorporated into a polyamide to provide a flame-retarded polyamide, as disclosed, for instance, in Japanese Patent Publication No. 47(1972)-41745 and Japanese Patent Provisional Publication No. 51(1976)-39750. However, these known flame-retardants have drawbacks in that the retardant is liable to sublime staining the mold when a polyamide composition containing the retardant is molded, or the retardant is liable to bleed out on the surface of a molded product in the form of a fine powder in the course of actual employment of the molded product, for instance, due to absorption of moisture. These behaviors of the known flame-retardants unfavorably degrades appearance of the molded product. It is further known that cyanuric acid or isocyanuric acid imparts to polyamide higher flame-retarding effect than melamine does. However, cyanuric acid and isocyanuric acid have additional drawbacks in that these are easily decomposed in the molding process to bring about foamy portions (cavities) into the molded product.
Japanese Patent Provisional Publication No. 53(1978)-31759 discloses a flame-retarding melamine cyanurate, namely, a reaction product between equivalent moles of melamine and cyanuric acid, for eliminating the drawbacks of the known retardants such as melamine, cyanuric acid and isocyanuric acid. The melamine cyanurate is improved in the above-described drawbacks attached to the known melamine, cyanuric acid and isocyanuric acid retardant. However, the melamine cyanurate still has disadvantageous feature that the flame-retarding effect provided thereby is lower than that provided by simple melamine or cyanuric acid. For this reason, the melamine cyanurate is not satisfactorily employed as a flame-retardant used in manufacture of electric parts for which high flame-retarding effect is needed.
Japanese Patent Provisional Publication Nos. 53(1978)-47451, 56(1981)-22347, etc. disclose that melamine derivatives such as methylenedimelamine and ethylenedimelamine are employable as flame-retardants for polyamide which are free from the drawbacks attached to the melamine, cyanuric acid and isocyanuric acid. According to studies of the present inventors, however, the flame-retarding effects provided by these melamine derivatives are still unsatisfactory even though the effects are higher than that provided by the aforementioned melamine cyanurate.